Blade Smithing & Tensioning

posted December 12, 2010 by: Editor

By: Kevin Baron – Western Saw Inc.

       Mike Nelson – K2 Diamond

What is smithing ?


n. 1. The act or art of working or forging metals, as steel, into any desired shape.

What is blade tensioning ?


v. 1. The process of neutralizing stresses in a disc of steel to allow it to cut with as little side play or wobble as possible.

Why do we need to smith & tension diamond blades and why is it important that we all understand these basic needs?  One thought is, we all want to obtain the absolute best value we can from diamond blades.  We also want to maintain high performance levels while we are going after that value.  A diamond blade will achieve its best value if it runs straight and true, which also reduces the chances of performance issues.

To get a diamond blade to run straight and true you need the right combination of factors and tool components.  Diamond blades have two primary components, the core and the diamond segments.  Assuming that the segments are “dialed in” to run just right for your particular application, we will focus on the blade core, which is made of steel. 

Believe it or not, steel is stretchable and contractible.  When steel is incorporated into an object that spins, the steel needs to be expanded or contracted and flattened, so that the object is “in balance” when spinning at a specific rotational speed.

In our industry we use the term “smithing” for the process of flattening and tensioning blades to run straighter, longer and safer at specific speeds.

Most diamond tool manufacturers have the capability to tension blades, and assist their clients in determining the specific saw RPM requirements.  Based on the client’s machine RPM, the blades are “tensioned” to run at the optimal speed for that specific diameter and type of diamond blade.  Once the diamond blade has been tensioned for a specific speed, it is critical that the blade be run at that speed for maximum and safe performance.

If the blade is run too slowly or too fast and is outside of the “tensioned window” the blade may start to wobble, vibrate, heat up and generally start a self-destruction mode.  That can lead to catastrophic failure of the blade, resulting in the possibility of personal injury or worse.

Can a diamond blade be re-tensioned?  Yes, blades can be re-tensioned as long as the core is in good condition and there are NO core cracks.  This will save you time and money and be much safer.  It takes a trained professional to tension, re-tension and level a blade properly.  Once completed, blades are then speed tested according to ANSI code B 7.1.  All US manufacturers are capable of this service.  

A good way to determine the proper speed that a diamond blade should run is to use the following formula to calculate the optimal blade speed for specific blade sizes.

Diameter of the Blade (in feet)  X  3.14  X  Machine RPM = Surface Feet Per Minute

(Example:  2 (24” blade) X 3.14  X  2000 (RPM) = 12,560 Surface Feet Per Minute)

Check with your diamond blade manufacturer to determine what they    recommend as the proper and/or optimal surface feet per minute speed.

Our industry has a very good trade association (CSDA) reviewing and recommending updates and changes to the standards and specifications that are specific to our sawing and drilling applications.  Our association committees work closely with government agencies to make sure that safety is primary when determining procedures and specifications.  ANSI has a code for blade tensioning, handling, care and use which is:


This code requires machine users to run wheels (diamond blades) at the correct speeds. Diamond blades must be smithed by a skilled saw smith. Blades are hammered and rolled to level and tensioned for specific speeds, which are marked on the blade.  Handling, care and storage of blades are the user’s responsibility.

 For further details please refer to the full listing of the ANSI.B.7.1 code.

Kevin Baron is the President of Western Saw, Inc., based in Oxnard, California.  Kevin can be contacted at 805.981.0999 or by email at;

Mike Nelson is VP Sales & Marketing of K2 Diamond based in Torrance, California.  Mike can be contacted at 800.539.6116 or by email at; mike.nelson@k2diamond.c